Method for maintenance of overhead line plants for telecommunications

ABSTRACT

A method or the realisation and the maintenance of overhead line plants for telecommunications, in which the anchor or “mooring” device of the self-gripping two-way supports of the cables, is made integral with a movable structure free to move along the supporting post. The structure includes a chain allowing lowering of the line from span level to ground level, and its successive lifting to the predetermined operative height at the end of the maintenance intervention. The lowering of the line to the ground level is achieved by exploiting the gravity force acting on the line itself, and the successive lifting, by pulling this anchor chain. The movable structures are provided according to different configurations, depending on the characteristics of the posts where these structures are used.

TECHNICAL FIELD

The present invention generally refers to the realisation, and to theexecution modalities for operation and maintenance of overhead lines fortelecommunications, comprising a cable sustained by posts, and moreparticularly it relates to movable anchoring or “mooring” devices whichpermit the realisation of the overhead line and the performance ofmaintenance works without the intervention of technicians at a certainheight above the ground.

BACKGROUND ART

The wide diffusion of the network formed by cables sustained by postsand the realisation modality of these plants, are critical with regardto operation and maintenance, in view of the costs involved, the servicequality, and the safety conditions during the execution of the work.

These critical aspects are essentially due to the requirement of theaccess of technicians at a certain height above the ground, and todifferent orographic and environmental characteristics of the territorywhere the posts are installed.

In fact, besides the stability conditions of the plants themselves, theactual environmental and orographic features of the territory willdetermine both the possibility of access to a position located a certainheight above the ground level, and the way this is to be done: use of acontrolled platform, a ladder, crampons (climbing irons).

Naturally, a comparison between the means employed and the time requiredfor the work, on the one hand, and the quality of the intervention andthe safety of the personnel, on the other hand, leads to differentresults, for each modality of access at a certain height above groundlevel, but in all cases they do not lead to optimum results.

An object of the present invention is to provide a method of realisationof overhead line plants for telecommunications via cable, whichradically limits the number of necessary interventions to be performedby the appointed technicians, at a certain height above the groundlevel.

A further object of the present invention is to provide a methodallowing the maintenance and the replacement of cables to be performeddirectly from the ground, thereby eliminating the need for access at acertain height above ground level.

Still another object of the present invention is to provide a method ofrealisation and maintenance of overhead line plants fortelecommunications, said plants crossing road paths, and wherein themethod allows the maintenance and the replacement of cables to beperformed directly from the ground, without the need of lowering theoverhead line to the road level and stopping vehicle traffic.

A last object of the present invention is to provide a method ofrealisation and maintenance of overhead line plants fortelecommunications, which employs standard components, materials andtechnologies in the field of fixed line telephone plants, so that theproposed devices used to carry out the method, will have limited costsand their use is facilitated.

DISCLOSURE OF INVENTION

These and other objects which will be clarified in the description, areobtained by means of a method according to which the mooring or anchordevice of the self-gripping two-way supports which sustain the cables,is made integral to a movable structure—and not to fixed points relativeto the post by the use of known threaded pins—, wherein the movablestructure is free to slide along the sustaining post and comprises achain allowing to lower the overhead line to the countryside groundlevel, and its subsequent lifting at the end of the maintenanceintervention. The lowering of the line to the ground level may beobtained by exploiting the action of the gravity force.

BRIEF DESCRIPTION OF DRAWINGS

Preferred embodiments of the invention will now be described forillustrative purposes only, without thereby limiting the generality andpossible applications thereof, by referring in the description to theannexed drawings, in which:

FIG. 1 is a schematic representation of a complete “mooring” or anchordevice, to be applied to a sectioning/junction post, in a rectilinearline section with four cables;

FIG. 2 is a schematic representation of an overhead telecommunicationline extending along a plurality of posts arranged on a rectilinearpath;

FIG. 3 is a schematic representation of a complete mooring or anchordevice to be used on a corner post;

FIG. 4 is a schematic representation of a plurality of fittings oraccessories in a movable mooring or anchor device;

FIG. 5 is a further schematic representation of an overhead line fortelecommunications, extending along a plurality of posts, with a changein direction of the line and a difference in height of the terrainbetween the posts 5 p and 6 p;

FIG. 6 is a schematic representation of an accessory or fitting, havinga the shape of a collar;

FIG. 7 is a schematic representation of an overhead line fortelecommunications, comprising a crossing section;

FIG. 8 is a schematic representation of a further set of devices,accessories or fittings, for a movable mooring device;

FIG. 9 is a schematic representation of a cable-supporting device, andof the associated pin with the sustaining ring;

FIG. 10 is a further schematic representation of an overhead line fortelecommunications, which extends along a plurality of posts, used toexplain the steps of an intervention in which a cable is removed fromthe corresponding buckle.

MODES FOR CARRYING OUT THE INVENTION

First of all, it must be noted that for clearness purposes the differentviews have been schematically drawn, in such a way that constructivedetails, whose presence is obvious but which are not relevant for thedescription of the relative embodiment, have been omitted from theviews, and in the latter the same component is always denoted by thesame numeral.

According to the kind of post, and to the function it performs,different realisations of specific, movable mooring (anchoring) devicesare provided, all having—however—the fundamental object to allowmaintenance works to be performed without the need of acceding to aposition at a certain height above the ground level.

Therefore, it is advisable to consider first of all, the different typesof posts present in an overhead line for telecommunications, which isused for cable transit and for related functions.

The line branches off from a starting post, which sustains the shunt (orbranch) box used for the branching off of the cables to the user;usually, according to the law in force, a number of cables between 1 andn, may branch off from said box.

Instead, a transit post is characterised only by the feature of having acable support buckle at its apex, at the span height; in practice, itsonly function is to support the cable span (cable bay).

A corner post is a post allowing a deviation of the line. In fact, thelatter may be forced to deviate from the normal rectilinear path,thereby changing its direction, due to terrain morphology or for anyother reason.

Moreover, it must be noted that cable coils (skeins) have a length of300 m, while the distance from one post to the next (usually calledspan) varies between 35 and 40 meters, so that, in practice, every eightposts there is a cable coil termination.

Therefore, a junction post is defined as a post where the end of thearriving cable coil is connected to the starting portion of a new cablecoil termination.

A sectioning post, is a particular kind of post comprised among theeight posts which usually define the 300 m-long cable section (it mayfor instance be located 150 m away from the starting post), and it isprovided for the following purposes:

to carry out tests, and

in order to be able to intervene, depending on the location of thefailure, by replacing only a limited cable section instead of the wholesection of coil length.

Moreover, it must be stated beforehand that in already existing overheadlines there is usually used at least a couple of self-pressing orself-gripping two-way supports, whose function substantially amounts totensioning the cable, besides making available a certain amount of cablestock length for the performance of cutting or reconnecting operationsin the course of maintenance works.

In the posts according to the prior art, said self-pressing orself-gripping two-way supports are—in fact—mounted in a fixed manner ona post, since the access by a technician, to a position located acertain height above the ground, is taken for granted, both during therealisation of the telecommunication line itself, when the cable is laidon the self-gripping support, and during the subsequent maintenance ofthe same.

The method according to the present invention, while resorting again tothe use of self-gripping two-way supports, provides for a movableanchoring thereof on the post, so that, after all, it will be shown howthe cable and its supports may be made to descend to the road/field(ground) level, thereby allowing a maintenance operation to be performedat ground level.

In order to simplify the description of the embodiments of theinvention, it is advisable to consider first of all—among the differentimplemented embodiments—, a particular structure which provides for theuse of an integrated device assembly, in order to carry out themaintenance method of overhead line plants for telecommunications, bythe use of a movable mooring (anchoring) apparatus. In the following,reference will be made to a structure mounted on the sectioning/junctionpost, which is used for possible ordinary maintenance works, and onlyafterwards we will discuss other types of embodiments.

The rectilinear line section is only a particular typology considered bythe present invention, and in this specific case the line ischaracterised by the transit of four cables, so that the stressesinvolved, acting on the anchoring or mooring devices, are four timeshigher than for line sections supporting a single cable. For thisreason, it is necessary that the technician is enabled to perform themaintenance work on the line, after the latter has been transferred tothe ground level, without any sort of unbalances being present in thetraction forces exerted between the cables of the line.

For instance, during the cutting and replacement operations of a singlecable among the four actually present on the line, the latter would besubjected to a traction in one direction, higher than in another one,and this unbalance of the forces present on the line, would certainlyrender more difficult the operation to be performed by a technician.

For these reasons, and in particular for the rectilinear section of theline, there is provided an anchoring or mooring device according to thepresent invention, which is positioned on the sectioning/junction postby the use of a chain of 2.50 m of length, which—as shown in FIG.1—supports a sort of small cage comprising an anchor element 21, in theform of an inverted “U”; on the latter, there are welded two spacers22′, 22″ with an elliptical, flattened configuration, which are hookedby four self-gripping supports 3′, 3″, 3′″, 3″″. This device is in facteffective for supporting even a greater number of cables and lines onthe same post.

The chain 25 may slide through the upper pin-ring 27′ and the lowerpin-ring 27″, thereby allowing lowering or lifting of the span level.Moreover, the chain 25 is fixed to two special hooks, being firstengaged with the hook retainer 28 at a level of about 4.50 m, andextending thereafter upwards to a height of 5.00 m, where it isultimately fixed by means of a safety hook which is not shown in FIG. 1,since it is disposed on the rear side of the post considering theorientation in this figure.

The disconnection of the chain from these two retainers, and thelowering of the span to a level corresponding to the height of a humanbeing, will only be possible by the use of a rod carrying a specificmeans or attachment.

Therefore, basically, it is possible to distinguish between two specificpositions of the line at a sectioning/junction post, that is:

I) line is operative at the span position, wherein the chain 25 sustainsfour self-pressing or self-gripping supports 3′, 3″, 3′″, 3″″, and isfixed by a first retainer 28 and by a second—safety—retainer which areboth fixedly arranged on the post, the first of said retainers beinglocated at a lower level than the second one;

II) the line is in the lowered state, or “maintenance state”, whereinthe chain 25 which still supports the four self-gripping devices 3′, 3″,3′″, 3″″ by means of the small cage 21, has been disengaged from saidretainers and has been made to slide, while hooked by a small ropeprovided with a spring catch, in order to be lifted again at the end ofthe maintenance operation.

From the strict point of view of the design, taking also account of theorder of magnitude of the distances involved in this application, thetwo anchor rings 27′, 27″ may be fixed at a height of 5.50-6.20 m,spaced apart from each other by a vertical distance of 10 cm, the saidrings being used for receiving the movable mooring—or anchor—devicehaving a cage-like configuration 21, whose lateral ends are hooked bythe self-pressing or gripping supports 3′, 3″, 3′″, 3′″ carrying thearriving line (incoming line) and the outgoing line.

The retainer 28 and the safety retainer, are both fixed on the samepost, at a height comprised in the interval 4.50-5.00 m.

The end 21 of the “mooring device”, is anchored to the chain, and thelatter, after having been unhooked, while sliding through the rings,allows lowering or lifting of the line. Under stability conditions thechain is fixed, in a stretched state, to both the fixing retainer andthe safety retainer.

The use of this “mooring” or anchor device may be better illustrated ifreference is made to FIG. 2, corresponding to a method of use of thedisclosed devices. In particular, said figure schematically shows asequence of posts arranged along a rectilinear path, wherein theequidistant posts denoted by E and I are considered to besectioning/junction posts, while the remaining posts, are considered tobe, for greater clearness, only transit posts.

Thus, supposing a failure has been noted and localised in the cablesection extending from I to E, then, the following steps must beperformed during the intervention:

1) the technician approaches the post E, and using the special rodequipped with a rope sustaining support and a section breakingdevice—the latter being widely described later on—, hooks the chain andreleases it from the safety retainer;

2) he removes the small rope from its support on the rod, and whileexerting a small downward traction force, he releases the chain from theretainers where it is anchored;

3) the release of the chain causes the lowering of the line to a levelcorresponding to the normal height of a human being; then, thetechnician locks—if necessary—the movable mooring device by means of alocking strap, and he cuts the damaged or broken cable;

4) he “temporarily” joins a new cable to the old one to be replaced;

5) he unhooks the chain from the post I as described in the aboveparagraphs 1, 2 and 3, he cuts the damaged or broken cable, and recoversthe cable section to be replaced, up to the temporary junction carryingthe new cable;

6) he joins the new cable to the outgoing one, and using the chain, hebrings the movable mooring device again to its seat at the apex of thepost; he hooks the chain to the fixing retainer and thereafter to thesafety retainer, and then he puts the small rope again in its positionin the special support provided on the rod, and unhooks the small ropefrom the chain;

7) at the post E, the technician snubs the replaced cable and fixes itto the self-gripping or self-pressing support; thereafter, he hooks theself-gripping support to the movable mooring device and performs thecable jointing operation, thereafter he releases the mooring device ifit was locked, and brings it again to its seat in the ring shaped hookat the top of the post;

8) he fixes the chain to the fixing and safety retainers, and herecovers the small rope as described in paragraph 6).

FIG. 3 exemplifies a movable mooring device for a corner post, whichsubstantially operates according to the above described steps concerninga movable mooring device for a sectioning/junction post, but which hasspecific features distinguishing it both functionally and structurally.

In fact, as schematically shown in FIG. 3, the couple of self-grippingor self-pressing supports 3′, 3″ is respectively anchored or “moored” ontwo supporting eyelets, 4′, 4″, which form the end elements of achain-guide 5, which may slide through a ring 6 rigidly connected to thepost, thereby allowing the lowering of the line located at the spanlevel, to the ground level, and the subsequent lifting at the end of themaintenance intervention. The outer diameter of each eyelet 4′, 4″exceeds the inner diameter of the ring 6, in order to prevent theirsliding through the ring itself, when the line is lifted again to itsupper level.

Therefore, basically, it is possible to distinguish two differentspecific positions of the cable and its supports:

I) the line is in its operative position at the span level, where in thechain 5 sustains the two self-gripping supports 3′, 3″ and the chain 5itself is retained by means of a first, or fixing retainer 9′, and by asecond, or safety retainer 9″, which are both arranged in fixedpositions on the post, wherein one of the retainers is located above theother and their mutual angular distance corresponds to 90°; the saidelements 9′, 9″ for preventing the chain from sliding, are substantiallyconfigured in such a way as to comprise a flat portion to be fixed tothe post surface, and an outgoing portion having two branches 8′, 8″which widen outwardly in a flaring configuration, thereby allowing toreceive the chain 5 and retain the latter, when it is pushed to theinside of limited width of the bifurcation 8′, 8″; chain sliding iseffectively prevented by the fact that the lateral dimension of a chainring of the chain 5 is greater than the width of the space between thetwo branches 8, in proximity of the base 7;

II) the line is in the lowered position or maintenance state, whereinthe chain 5, which still sustains both self-pressing supports 3′, 3″ bymeans of the two eyelets 4′ and 4″, has been released from saidretainers or locking elements 9′, 9″ and has been made to slide whilehooked by a small rope provided with an eyelet or loop, in such a way asto be able to bring the line again to the upper level, after themaintenance intervention.

Under a strict point of view of the design, taking also account of theorder of magnitude of the dimensions involved, it is convenient toprovide the ring hook 6 on the post at a height of 5.50-6.20 m, and toprovide a corner chain 5, which is capable of sliding therein and havingthe two eyelets 4′, 4″, with a length comprised between 1 m and 1,20 m,the said chain hooking—as described above—the two self-gripping supports3′, 3″ of the line.

At lower height, of 30-50 cm with respect to the ring hook 6, there isfixed the fixing retainer 9′ and the safety retainer 9″, on which thechain is locked.

In a further embodiment of the chain 5, the latter has an “Y”configuration, that is it as a branching off with two arms, each havinga length of about 10 cm and an end forming an eyelet 4. This kind ofbifurcated configuration of the chain allows its more versatile useunder certain conditions, like the presence of differences in height(unevenness of the ground) or obstacles preventing the technician fromoperating from an optimum position. In fact, in this situation it mayhappen that during the unhooking operation by the technician, the chainwill not be long enough to lower the line to the ground level of thecountryside, since the different pile-driving levels may cause the cableto rise, on one side, for a certain distance. These extensions providedon the end of the chain, have the effect of making available anincreased length and a certain degree of freedom in the movements, so asto facilitate the adjustment of the line through a momentary and movingaway lowering movement or a momentary lifting and moving away movement.

The release of the chain 5 from its locking elements 9′, 9″, in order toperform the restoration of the line, and in order to adjust the descentstroke and lifting stroke of the chain, is obtained by means of specialdevices.

The use of these special devices, which will be described below, enablesthe technician to make these kind of interventions on the line, andprevents at the same time any act of vandalism.

In particular, in order to carry out the release operation of themooring devices or anchor devices that have been described previously,and in order to perform other kinds of interventions which will beexplained below, the technician avails himself of a telescopic rod 16made of plastic reinforced by fibre glass, and of a set of replaceableterminal supports.

For carrying out all kinds of interventions, on posts provided with theabove specified equipment, the telescopic rod sustains a hollowtransport device 15, of the kind shown in FIG. 4A.

This device substantially comprises two elements forming a single body:

a hollow cylinder 14, of a slightly greater diameter than that of thetelescopic rod 16, in such a way as to be fitted and retained thereon,and

a portion of a hollow cylinder 17, which is open on one side, therebyallowing to insert therein a small rope 18 with a loop or eyelet 19.

In practice, when the technician releases or unhooks the line, heintroduces first the loop or eyelet 19 of the small rope, on the hook 20forming the lower termination of the chain 5, by using the telescopicrod; then, he removes the small rope 18 from its seat 17, and uses thesmall rope in order to unhook the chain 5 from the retainers 9′ and 9″.Thus, the chain 5 will be free to slide and will enable the lowering ofthe line under the action of its own weight, whereas the liftingoperation and the locking in the retainers 9′ and 9″ may be performed atthe end of the intervention, by pulling the small rope and therefore thechain 5 connected thereto by means of the hook 20.

Moreover, this telescopic rod is provided with a section breakingdevice, as shown in FIG. 4B, that is of a special element used toprevent undesirable oscillations and flexion of the support rod, duringthe various uses of the rod at a certain height above the ground level,both when the latter sustains an anchor or release device, and when itsustains a device for the introduction of the cable at the time the lineis realised, as disclosed below.

From the structural point of view, this section breaking device forms aremovable half-collar 30, which is fixed, depending on the kind ofintervention, in an approximately intermediate and adjustable positionon the rod—which is in fact 4 to 5 meters long—, in order to allow toperform an intervention at a predetermined height. Actually, due to thishigh length value, the rod could be subjected to flexion oroscillations, so that the arrangement of said section breaking device,provided with a concave portion 31 of the half-collar which faces thepost and leans against it in a stable position, has the effect ofeliminating said undesirable flexion and oscillations.

The use of the mooring devices which have just been described, may bebetter understood with reference to FIG. 5, which refers to anintervention on a section of the line, which includes a difference inheight and a change in direction.

In the situation which is schematically shown, it is supposed that thelowering of the overhead line to the ground level of the countryside, isperformed by means of a chain with two arms, provided on the post 5 p,at which location the line changes in direction and crosses a road of afarm.

Supposing the existence of a failure at 150 m, it is decided to replacethe cable section starting at the distributor supporting post and endingat the post 5 p. Then, the following operative steps may be identified:

1) the technician approaches the post 5 p, and by means of the specialrod, equipped with the small rope support and with the section breakingdevice, hooks the chain and releases it from the safety retainer;

2) he removes the small rope from the small rope support on the rod, andby means of a pulling action exerted first externally and then upwardly,he unhooks the chain from the fixing retainer;

3) the release of the chain causes the lowering of the line to theground level, so that the damaged cable to be replaced may be removedfrom the self-pressing support and may be cut; then, the line can bebrought again to a safety level by fastening the small rope at the postbase; subsequently, a new cable is “temporarily” jointed to the oldcable to be replaced;

4) at the location of the distributor-supporting post, 1 p, theself-gripping or self-pressing support is released from the small bandwhich retains the elliptic collar—see details below—;

5) the old cable to be replaced is recovered up to the temporary jointwhich holds the new cable;

6) at the location of the post 5 p the line is once again lowered to theground level, the new cable is jointed to the outgoing one, whereafterthe line is again lifted to the operative level;

7) the chain is hooked to the fixing retainer 9′ and to the safetyretainer 9″, in this order, and then the small rope is again insertedinside the special support on the rod, and is released from the hook 20forming the lower termination of the chain;

8) at the location of the distributor support post, 1 p, the cable issnubbed and fixed to the self-pressing support, while the latter ishooked to the small band which retains the elliptic collar;

9) the small cable is connected to the distributor.

For what concerns the equipment of the starting post, on the other hand,the problem briefly amounts to the fact that the latter supports fourcables which are connected—that is screwed—to a distribution box, andare made to extend upwardly, till they reach the line span level; inconventional overhead lines, the said box is fixed at 3.50 meters, andthe cable extends upwards to a height of 5.50 meters, in order to beintroduced inside the self-gripping, two-way support. More specifically,these cables extend from a terminal board and are lodged inside aplastic-made protection raceway, which reaches the top of the post,where the cables of the span are tensioned by means of the self-grippingtwo-way supports, which are fixed by means of a threaded pin to the postitself, at the span level. Due to the fact that these pins arepermanently driven in the post, the mooring device is itself fixed, sothat the self-gripping two-way device can in no way be removed, loweredto the ground level, and lifted again to the operative position.

According to the method devised by the present invention, theself-gripping support is not fixed anymore at the upper position,integral to the pin, but is fixed instead to a collar of the kindillustrated in FIG. 6; in practice, above the distributor, and at aheight of 3.30 m, there is fixed an elliptic collar 32 with bandretainer, to which there is anchored a couple of self-gripping supports,supporting one or more cables, whereas at a height of between 5.50 and6.20 meters, there is positioned a mesh collar for hooking the two-waycable guide, for the transit of the line at span level.

The elliptic collar 32 comprises two half-collars, which enclose thewhole circumference of the post. FIG. 6 shows the most significanthalf-collar 34, for the purpose of the invention, which is characterisedby the fact that it comprises a support structure for the self-grippingdevices. In fact, the three projecting small rods 35′, 35″, 35′″, andthe transversally inserted rod iron 36, make up the hooking element forthe self-gripping supports, as the rod iron 36 is separated by thecentral projecting element 35″ in two distinct sections, each of whichmay support a self-gripping two-way device.

Since the latter is arranged at a height of 3.30 meters, the technicianmay reach said supports by using a single ladder element, therebynoticeably reducing the risks of the intervention. Moreover, the accessof the technician at a height of 3.30 m is already foreseen duringordinary maintenance, since the technician must in any case reach theterminal board in order to perform ramification (branching-off)interventions: therefore, he may in the same way have access to thecollar 34 in order to effect maintenance interventions on the startingpost.

The collar has been realised in such a way as to be capable ofsupporting two self-gripping two-way devices, and since eachself-gripping device is suited to hold two cables, it is possible toimplement a line with four cables, complying in this manner with thebody of technical rules, according to which the number of single cablesmust be less than five in the realisation of subscriber's overheadlines.

The collar described in the above section and used in a starting post,is also of fundamental importance for the equipment of posts used inoverhead lines crossing roads or the like.

In fact, also in this application, the elliptical collar 32 with bandretainer is fixed at a height of 3.30 meters, and the two self-grippingsupports which support the line, are anchored thereon.

At a height comprised between 5.50 m and 6.20 m, there is fixed afurther elliptical collar, and to the latter there is fixed the steelrope which supports, by means of clamps or clips, a PVC tube containingthe overhead line which crosses the road. At a smaller height, there ispositioned the mesh collar, to which there are hooked the incoming andoutgoing two-way cable guides.

To carry out the intervention on the line section, in order to replacethe cable on a crossing cable span, the following two steps are providedfor, as schematically shown in FIG. 7:

the technician approaches a first post 12 p and releases the damagedcable to be replaced from the self-gripping device, he cuts the cableand temporarily joints it to a new cable;

he approaches the other post 13 p, releases the damaged cable from theself-gripping device, and pulls it towards himself until he finds thetemporary joint which carries the new cable;

he fixes the new cable on the self-gripping device and he definitivelyjoints it to the outgoing (continuing) cable;

he goes back to the post 12 p, snubs the cable, fixes it in theself-gripping device, and effects the definitive joint with the outgoingcable extending in the other direction;

In FIGS. 8A and 8B there are shown further accessories or devices usedfor the realisation of the apparatus of the invention. FIG. 8A shows thetelescopic rod carrying the special section breaking device 30.

The telescopic rod, in this case, carries at its distal end abuckle-supporting and probe-guiding support, which is bent to an “L”shape and has an exit aperture 41 which is cut away and flared. Thisspecific configuration of the device allows to receive the cablesupporting buckle 71 of FIG. 9, and moreover, the introduction of aprobe which is made to slide inside the cable supporting buckles 71 ofthe transit posts, carrying directly from the ground the cable to beinstalled or replaced, till it reaches its predetermined position.

Particularly for the starting posts, the probe-guiding support 40 hasthe most advantageous configuration in order to insert the probe and thecable, together, inside a sleeve 42 of the kind shown in FIG. 8B, whichmay be oriented and which is anchored to a hook of the post by means ofthe ring 43.

The use of the devices which have been just described, may be betterunderstood by referring to FIG. 10, for instance, which exemplifies amaintenance intervention of cable replacement, when the latter has comeout of the buckles due to mechanical breakage, wherein the followingsteps are provided for:

1—at the post 24 p, the technician lowers the line to the countrysideground level, and cuts the cable to be replaced;

2—at the central post 23 p the technician, by using the telescopic rodand a probe-guiding support, causes the probe to slide inside thecable-supporting buckle 71, from the left to the right, that is, withregard to FIG. 10, in the direction from 23 p towards 24 p;

3—he temporarily joints the new cable to the head of the probe;

4—he pulls the probe again in order to thread the cable in the buckle;

5—he goes to the post 22 p which precedes the central post 23 p andrepeats the operation already described;

6—at the post 21 p he lowers the line to the countryside ground level,he cuts the old cable and joints the new one to the outgoing cable(cable continuation) and he lifts the overhead line back to the spanlevel;

7—he goes to the post 24 p, snubs and fixes the new cable to theself-gripping device, he realises the joint with the outgoing cable, andfinally brings the line again to the operative position.

Industrial Applicability

Interventions performed for test purposes, on the plants installed asdescribed above, have lead to optimum results with regard to the totaltime needed for the intervention, and with regard to the effectivenessof the final result of the intervention.

It is obvious from the description, that the system is versatile and iscertainly not configured for a single typology of posts. Taking accountof the variety of orographic conditions of the terrain where the postsare installed, it may be noted that the system disclosed by the presentinvention has solved all possible cases which may arise in practice(although it frequently happens to have the possibility to work on acompletely rectilinear section of the line, this situation may be onlytheoretically generalised to all situations, since technicians oftenhave to deal with continuos changes in direction, road crossings,difference in height due to orographic reasons, environmentmodifications, etc.). A further advantage may be seen in the modularityof the devices of the present invention, so that the technician whoknows the kind of intervention and the type of section where the latteris to be performed, may select in advance the set of devices he needs.In any case, the greatest advantage is obtainable when the complete setof devices is available, since a single technician is thereby enabled toalways perform resolutory operations at the time of first interventionand under completely safe conditions, even if he does not know inadvance neither the kind of failure or defect, nor thetechnical/environmental condition of the posts and of the terrain.

What is claimed is:
 1. A movable apparatus, for mooring or anchoringself-gripping supports in a telecommunication line, in which the mooringor anchor device of self-gripping two-way devices which carry cables, ismade integral with a movable structure, which may freely slide a along asustaining post, said structure comprising an anchor chain (25),allowing lowering of the line to ground level and successive lifting ofthe line to the operative position at the end of maintenance; saidlowering of the line being obtained by exploiting the gravity forceacting on the line itself, and the subsequent lifting to the operativeposition of said mooring or anchor device, being obtained by a tractionof said anchor chain exerted by the operator, said apparatus being,characterised in that it is positioned on a post and in that said chainsupports an anchor element (21) having an inverted “U” configuration, onwhich there are welded two spacers (22′, 22″) with a flattenedelliptical shape, which are hooked by four self-gripping supports; thesaid chain adapted slides through an upper, shaft bearing ring (27′),and through a lower, shaft bearing ring (27′), in order to allow thelowering or the lifting of the line, and the said chain being fixed to afirst hook and a second hook, wherein said chain is to be locked in afirst position to the first hook (28) at about 4.00 meters of height,and in a further, more elevated position, at about 5.00 m, to the secondhook, in which said chain is fixed.
 2. A movable apparatus according toclaim 1, characterised in that said chain has a length of 2.50 meters.3. A movable apparatus according to claim 1, characterised in that itcomprises telescopic means allowing the access to the post and therespective mooring device, and interacts with a set of interchangeablesupports, including a device with a hollow double cylinder (15), abuckle-supporting and probe-guiding support (40) and a section breakingdevice (30).
 4. A movable apparatus according to claim 3, characterisedin that the hollow double cylinder (15) comprises two integrally formedelements: I-a firs hollow cylinder (14) having a slightly greaterdiameter than the diameter of the telescopic rod (16), so as to befitted and retained on the latter, and II-a section of a hollow cylinder(17), which is open on one side, in such a way to allow the insertion ofa small rope (18) which supports a rope loop (19).
 5. A movableapparatus according to claim 3, characterised in that said sectionbreaking device (30) is a removable half-collar, which is fixed in anintermediate and adjustable position along the telescopic rod, in orderto ensure its safe use at a certain height, thereby eliminating anyflexion or oscillations of the rod; the said section breaking devicebeing positioned so as to face the post with the concavity of itshalf-collar, thereby leaning on the post and ensuring stability of thepost.
 6. A movable apparatus according to claim 3, characterised in thatthe buckle-supporting and probe-guiding support (40) has a bent,L-shaped configuration, with its exit opening (41) partially cut awayand flared, thereby being suited to receive a cable supporting buckle(71) and allowing the insertion of a probe, which is slid inside thecable supporting buckles of the transit posts, and allows carrying thecable to be installed or replaced.
 7. A movable apparatus mooring oranchoring self-gripping supports in a telecommunication line,characterised in that it is located on a post, and in that it comprisesa pair of self-gripping supports respectively moored to two supporteyelets (4′, 4″) forming end elements of a guide-chain (5), wherein saidguide chain is, by sliding inside a ring (6) integral with the post,lowers the line and subsequently lifts the line to an operative positionafter maintenance, by the use of a small rope (18); the chain (5) beinglocked by a first retainer (9), and by a second retainer (9′), bothretainers being rigidly connected to the post at different heights; saidretainers (9′, 9″) comprising a flat portion to be fixed to the surfaceof the post, and a projecting portion forming a bifurcation (8′, 8′),which widens outwardly and is flared, so as to allow the insertion ofsaid guide-chain (5) and the locking of the guide-chain, once theguide-chain has been pushed towards an inner narrowed portion of thebifurcation (8′, 8′).
 8. A movable apparatus according to claim 7,characterised in that said guide-chain (5) has a length of 1.20 meters.9. A movable apparatus according to claim 7, characterised in that itcomprises the guide-chain (5) of 1.20 meters of length, having a “Y”configuration, including a ramification with two arms, each having alength of the order of 10 cm and ending respectively in an integrallyformed eyelet.
 10. A movable apparatus according to claim 7,characterised in that it further comprises an elliptic collar (32) witha retainer band, including two half-collars; one of said collars beingprovided with three projecting elements having a transversely insertedrod which forms the anchor element, and the central one (35″) of saidprojecting elements separating the rod iron in two sections; each ofthese sections supporting a self-gripping two-way device and itsrespective cables.
 11. A method for maintenance of overhead lines fortelecommunications, characterised in that for the replacement of a cablein a long, rectilinear line section, the following operative steps areperformed: I-at a first sectioning post (E), an operator hooks andreleases a chain from a safety retainer, using a rod, with the supportof a small rope and a section breaking device; II-the operator removesthe small rope from its support on the rod, and by exerting a slightdownward traction, unhooks the chain from a fixing retainer; III-theunhooking of the chain, causes the downward displacement of the lines toa height corresponding to an individual's average height; then, themovable mooring device is fixed on the post by means of a locking strap,and the cable is cut; IV-a new cable is temporarily joined o the oldcable to be replaced; V-the chain is released from a second sectioningpost (I), and the cable is cut and recovered up to the temporary jointcarrying the new cable; VI-the new cable is joined, and through thechain, the movable mooring device is brought back to a seat at the topof the second post; the chain is hooked to the fixing retainer and thento the safety retainer, and the small rope is inserted again inside itssupport on the rod, and finally the small rope is unhooked from thechain; VII-at the first sectioning post, the operator fixes the cable tothe self-gripping support and snubs it; then, the self-gripping supportis hooked to the movable mooring device and a junction is formed; then,the device is released, and is brought back to its seat in the ring hookat the top of he post; VIII-the chain is fixed to the fixing and safetyretainers and the small rope is recovered.
 12. A method as in claim 11,wherein an extended section of the lines and a change in direction are,characterised in that for the replacement of a cable along said extendedsection and a change in direction, the following steps are performed:I-a technician (a) detaches the cable to be replaced, from adistributor; II-another technician (b) approaches a post (5), unhooksthe chain in order to lower the overhead line, releases the old cable tobe replaced from the self-gripping support and cuts it; then, hetemporarily joins the old cable to the new cable, and brings the linesagain into a safety position at a predetermined height; m-the firsttechnician (a) operating from a distributor supporting post (1 p),unhooks the self-gripping support from a band retainer of a mooringcollar, releases the old cable, and by pulling it towards himself,begins to recover the same; IV-after he has found the temporary jointcarrying the new cable, the technician (a) releases the new cable andcommunicates this fact to the other technician (b); V-the othertechnician (b), from the post (5 p), lowers the line again, and locksthe cable in the self-gripping support, effects the joint, brings theline again to its operative position at the predetermined height, andfinally fixes the chain to the fixing and safety retainers; VI-from thedistributor supporting post, the technician (a) snubs the cable, hooksthe self-gripping support to the mooring or anchoring collar, andperforms an electrical connection of the line in order to restoreservice.
 13. A method according to claim 12, said overhead lineincluding a section thereof which crosses a road, characterised in thatfor the crossing of road, a PVC tube is used which has an internaldiameter of a size allowing the transit of cables, so that the repair orreplacement of these cables may be performed without being forced tolower the line to the road level, and therefore without blocking vehicletraffic.
 14. A method according to claim 13, characterised in that forthe replacement of a cable at a crossing span, the technician makes useof the following steps, while working at the distributor's height: I-atthe location of the first crossing post (12 p), he releases from theself-gripping support arranged at the distributor level, a damaged orbroken cable to be replaced, he cuts it, and temporarily joins the newcable; II-he goes to the other post (13 p), releases the damaged orbroken cable from the self gripping support located at the distributorlevel, and pulls it towards himself, until he finds the temporary jointcarrying the new cable; he locks the new cable on the self-grippingsupport and effects the joint; IV-he goes back to the initial post (12p), snubs the cable, locks it in he self-gripping support, and forms ajoint.
 15. A method according to claim 11, said overhead line includinga section thereof which crosses a road, characterised in that forcrossing of the road, a PVC tube is used which has an internal diameterof a size allowing the transit of cables, so that the repair orreplacement of these cables may be performed without being forced tolower the line to the road level, and therefore without blocking vehicletraffic.
 16. A method according to claim 15, characterised in that forthe replacement of a cable at a crossing span, the technician makes useof the following steps, while working at the distributor's height: I-atthe location of a first crossing post (12 p), he releases from theself-gripping support arranged at the distributor level, a damaged orbroken cable to be replaced, he cuts it, and temporarily joins a newcable; II-he goes to the other post (13 p), releases the damaged orbroken cable from the self-gripping support located at the distributorlevel, and pulls it towards himself, until he finds the temporary jointcarrying the new cable; he locks the new cable on the self-grippingsupport and effects the joint; IV-he go a back to the initial post (12p), snubs the cable, locks it in he self-gripping support, and forms ajoint.